php mysql留言板点赞

CREATE TABLE messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    content TEXT NOT NULL,
    user_id INT NOT NULL
);

CREATE TABLE likes (
    id INT AUTO_INCREMENT PRIMARY KEY,
    message_id INT NOT NULL,
    user_id INT NOT NULL,
    liked_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (message_id) REFERENCES messages(id)
);

<?php
// 假设已连接到数据库
$messages = $db->query('SELECT * FROM messages')->fetchAll();

foreach ($messages as $message) {
    echo "<p>{$message['content']}</p>";
    echo "<button onclick='likeMessage({$message['id']})'>点赞 ({$getLikesCount[$message['id']]})</button>";
}
?>

<?php
if ($_SERVER['REQUEST_METHOD'] == 'POST' && isset($_POST['message_id']) && isset($_SESSION['user_id'])) {
    $messageId = $_POST['message_id'];
    $userId = $_SESSION['user_id'];

    // 检查用户是否已经点过赞
    $alreadyLiked = $db->query("SELECT * FROM likes WHERE message_id = $messageId AND user_id = $userId")->fetch();

    if (!$alreadyLiked) {
        // 插入新的点赞记录
        $db->exec("INSERT INTO likes (message_id, user_id) VALUES ($messageId, $userId)");
    } else {
        // 用户取消点赞
        $db->exec("DELETE FROM likes WHERE message_id = $messageId AND user_id = $userId");
    }

    header('Content-Type: application/json');
    echo json_encode(['success' => true]);
    exit;
}
?>

function likeMessage(messageId) {
    fetch('like.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/x-www-form-urlencoded',
        },
        body: `message_id=${messageId}`
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            // 更新点赞数显示
            const likeButton = document.querySelector(`button[onclick="likeMessage(${messageId})"]`);
            const likeCount = parseInt(likeButton.innerText.split(' ')[1]);
            likeButton.innerText = `点赞 (${likeCount + 1})`;
        }
    });
}